“穷举法”

#include<iostream>
using namespace std;
int main()
{
	int a,b,c,count=0;
	cout<<"小明借书给三位小朋友的方案有： "<<endl;
	for(a=1;a<=5;a++)
		for(b=1;b<=5;b++)
			for(c=1;c<=5;c++)
				if(a!=b&&c!=a&&c!=b)
				{
					++count;
					cout<<count<<": "<<a<<","<<"b"<<","<<c<<endl;
				}
				return 0;
}

运行结果：